Outboard motor with planing surface



y 7, 1957 C. p. STRANG 2,791,196

OUTBOARD MOTOR WITH PLANING SURFACE Filed April 18, 1955 2 Sheets-Sheet1 E INVENTOR. [HAPLZES l). $7PAN6 ZMMQ A A TTORNEV -INVENTOR.

2 Sheets-Sheet 2 C. D. STRANG OUTBOARD MOTOR WITH PLANING SURFACE May 7,1957 Filed April 18, 1955 FIG. 2.

(HA/MES STWANG United States Patent OUTBOARD MOTOR WITH PLANING SURFACECharles D. Strang, Oshkosh, Wis., assignor to Kiekhaefer Corporation,Cedarburg, Wis., a corporation of Wisconsm This invention relatesto'ou'tboard' motors particularly for boats which Operate on theprinciple of the hydroplane. I

According to the invention, a dirigible planing surface is disposed toride on the surface ofthe water and hydrodynamically support the rear ofthe boat.

More specifically the invention comprises an outboard motor unit havinga streamlined gear case at the lower end of the motor and provided withthe planing surface beneath the gear case and immediately in front ofthe propeller angularly disposed to ride on the surface of the water andto hydrodynamically support the rear of the boat out of the water andthe propeller a given distance in the Water.

The propeller is carried at the rear of the gear case on a substantiallyhorizontal shaft journally supported within the gear case and driven bythe engine. The motor unit including the gear case and propeller isdirigible with respect to the boat to effect directional control of theboat, and the angularly disposed planing member formed integrally withthe gear case is dirigible therewith.

The object of the invention is to support the boat with a minimum ofdrag.

The drawings furnished herewith illustrate the best mode of carrying outthe invention as presently contemplated and set forth hereinafter.

In the drawings:

Figure 1 is a side elevation showing the motor and boat in the positionin which the boat is supported at planing speeds;

Fig. 2 is an enlarged side elevation partially in section of the motorunit and transom end of the boat and with one supporting clamp of themotor removed; and

Fig. 3 is a sectional view taken on line 3-3 of Figure 2.

The boat 1 shown in the drawings includes the transom 2 which carriesthe outboard motor unit 3 at the rear of the boat to propel the same andincludes the step 4 located slightly forwardly of the center of gravityof the boat and intermediate the forward and rearward planingunder-surfaces 5 and 6, respectively. Boat 1 is of the hydroplane typewherein the boat is supported independently of its normal displacementabove certain speeds by the dynamic reaction of the water to themovement of the planing surfaces.

The outboard motor unit 3 as shown includes the hollow drive shafthousing 7 having an open upper end supporting the base of the engine 8which is enclosed by the cowl 9 and connected by the drive shaft 10 tothe lower propeller unit 11.

The lower propeller unit 11 includes the streamlined strut 12 secured tothe lower end of housing 7 beneath the horizontal plate 13 which extendsrearwardly over the propeller 14. The enlarged streamlined torpedoshapedgear case 15 of the lower unit 11 is disposed forwardly of the hub ofthe propeller and encloses the gears, not shown, which drivingly connectshaft 10 and the propeller shaft 16, indicated by dotted lines.Propeller 14 is disposed rearwardly on shaft 16. The skeg 17 2,791,196Patented May 7, 1957 ICC extending downwardly from gear case 15 ahead ofpropeller 14 serves to protect the propeller against damage by objectsin the water passing beneath the boat.

Motor unit 3 is secured to boat 1 by the bracket assembly which includesthe two laterally spaced clamps 18 provided with the turn screws 19 forfastening to the upper end of transom 2 of the boat. The tilt-bracket 20is carried by and between clamps 13 on the pin 21 for pivotal movementon a transverse axis respecting the boat, and is provided with thevertical swivel pin 22 having upper and lower ends fitted with thecushion elements 23. The upper and lower lugs 24 formed integrally withhousing 7 and forwardly thereof are mounted on cushion elements 23 andsupport the motor unit 3 for pivotal movement as by the tiller 25 on avertical axis for the directional control of the boat.

' According to the invention, the planing member 26 having a forwardangle of incidence for lifting and the positive support of the rear ofthe boat is fixed beneath gear case 15 so as to be both adjustable anddirigible with the motor unit on the tilt pin 21. and swivel pin 22,respectively. 7

The adjustment ofthe motor unit 3 on pin 21 allows the angularity of thepropeller shaft and the direction of thrust of the propeller to bechanged in either direction from the normal horizontal shown in thedrawings. Adjustment of the motor unit 3 on pin 21 from the positionshown so that the thrust of the propeller is directed upwardly willeffect a greater lifting of the rear of the boat and efiects acorresponding increase in the angle of incidence of member 26 to providea corresponding increase in lift as desired. The desired angularadjustment of the motor unit 3 is maintained by the cross bolt 27 whichis selectively disposed in corresponding opposite holes of the series ofholes 28 in the lower rear portions of the clamps 18 and to be engagedby tilt bracket 20 which limits movement of the motor unit on pin 21 inone direction only. The pivotal movement of the motor unit allowed inthe other direction permits the motor to tilt and the lower end to passover a submerged object, or to be raised from the water. motor theforward thrust of the propeller is received by bolt 27 which normallymaintains the motor unit in the selected position of adjustment.

The adjustment of motor unit 3 on the vertical axis of pin 22 determinesthe direction of thrust of the propeller and the direction of movementof the boat. In the course of turning, the actual movement of the boatincludes a sideward component and does not correspond to the directionallines of the boat. The position of planing member 26 is changed withsteering movement of motor unit 3 so that the forward angle of incidenceis altered toward the outside of the turn and member 26 faces in thedirection of the actual movement referred to.

Motor unit 3 is secured to boat 1 so that planing member 26 supports theboat with rear undersurface 6 clear of the water and so that member 26with the forward undersurface 5 of the boat provides the entire supportof the boat at planing speeds. Member 26 also maintains gear case 15 outof the water at planing speeds. Member 26 has a rear, trailing edgelocated immediately in front of propeller 14 and extends beneathpropeller shaft 16 so that only the lower blades of the propeller aresubmerged at the planing speeds referred to. The proximate relationshipof member 26 and propeller 14 provides the support of the propeller atthe same depth in the water at all times and generally regardless of upto moderate waves and swells. While the invention is not intended forparticularly rough water the member may drop below the level of thewater momentarily, as in rough water, without causing undue drag becauseof In the operation of the a the relatively small area required for thenormal support of the rear of the boat when such support is adjustableas described and is dirigible to correspond at all times generally withthe direction of actual movement of the boat.

Various modes of carrying out the invention are contemplated as withinthe scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. .In an outboard motor unit including a powerhead, asubstantiallyvertical housing supportingthe powerhead, a gear-case fixed to the lowerend of the housing, a propeller shaft journally supported Within thegear case and being driven bysaidpower head, and a clamp bracketassembly for securement to a boat and pivotally conneeted'to the housingfor steering movement of the unit to effect the directional control ofthe boat; a planing member integral with the gear case and'dirigibletherewith provided immediately forward of the propeller, said memberhaving a lower planing surface disposed angularly and beneath the gearcase to'plane the surface of the water at planing speeds and maintainthe gear case and rear of the boat out of the water with the propeller agiven distance in the water.

2. In an outboard motor unit for securement to a 'boat, a powerhead, asubstantially vertical housing supporting the powerhead, a gear casefixed to the lower end of the housing, a propeller shaft disposed withinthe gear case and being driven by said powerhead, a

propeller disposed rearwardly on said shaft, and means disposed beneathsaid gear ease and forwardly of the propeller to support the gear caseand the rear end of the boat out of the water at planing speeds tominimize drag, said means being inclined and having a trailing portionextending beneath said propeller shaft so that only a portion of thepropeller is submerged at planing speeds.

